hid bootloader for pic18F2550

Hi everyone,

I have a problem trying to flash the program into
pic18F2550 using HID bootloader.

I managed to compile and programmed the microcontroller
with the hid bootloader.
I also managed to use the hid bootloader pc software
to load my application firmware into the bootload microcontroller.

However I can only do it only once.
After using the bootload to load the application firmware,
the microcontroller can no longer return to the bootloading mode.

I believe that my application linker file may have been modified wrongly.
The following is my linker file which I modified to reserved program memory from
0x0000 to 0x0FFF for the bootloader.
Hope that you can provide me further advise,
what I may have missed out.

Thank you for your help.
Siong Boon


// File: 18f2550 - HID Bootload.lkr
// Sample linker script for the PIC18F2550 processor
// Modified for pic18f2550 bootloader

LIBPATH .

FILES c018i.o
FILES clib.lib
FILES p18f2550.lib

CODEPAGE NAME=bootloader START=0x0 END=0xFFF PROTECTED
CODEPAGE NAME=vectors START=0x1000 END=0x1029 PROTECTED
CODEPAGE NAME=page START=0x102A END=0x7FFF
CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED

ACCESSBANK NAME=accessram START=0x0 END=0x5F
DATABANK NAME=gpr0 START=0x60 END=0xFF
DATABANK NAME=gpr1 START=0x100 END=0x1FF
DATABANK NAME=gpr2 START=0x200 END=0x2FF
DATABANK NAME=gpr3 START=0x300 END=0x3FF
DATABANK NAME=usb4 START=0x400 END=0x4FF PROTECTED
DATABANK NAME=usb5 START=0x500 END=0x5FF PROTECTED
DATABANK NAME=usb6 START=0x600 END=0x6FF PROTECTED
DATABANK NAME=usb7 START=0x700 END=0x7FF PROTECTED
ACCESSBANK NAME=accesssfr START=0xF60 END=0xFFF PROTECTED

SECTION NAME=CONFIG ROM=config

STACK SIZE=0x100 RAM=gpr3

SECTION NAME=USB_VARS RAM=usb4